The present invention relates to a detent changeover switch apparatus capable of changing over click feeling generated by an operation portion of an operation switch.
Conventionally, as an input operation system for performing operation setting of various vehicle-loaded equipment such as an air conditioner and an audio device, various kinds of operation switches are mounted on a vehicle corresponding to respective functions. As one example, with respect to the operation switches of the air conditioner, for example, a temperature setting switch for setting a supply-air temperature, an air volume setting switch for setting an air volume, an air blow direction setting switch for setting an air blow and the like are used. As such a group of switches, a rotary operation switch, that is, a rotary switch which performs setting of various functions by rotatably operating a dial knob of a rotary operation type as an operation portion has been popularly used.
Further, this kind of rotary switch is provided with a detent mechanism capable of imparting a desired operation force or click feeling to the dial knob as a click for ensuring an operation of the dial knob by enhancing operation feeling of the dial knob. In general, the detent mechanism is configured such that the detent mechanism includes the dial knob rotatably operated by an operator and a casing which rotatably supports the dial knob, a plurality of detent crests which is arranged between the dial knob and the casing and is formed on one of the dial knob and the casing along the rotational direction of the knob, a detent piece which is always biased to the detent crest due to a biasing spring is mounted on the other of the dial knob and the casing, and operational force which is generated when the detent piece gets over the detent crest due to the rotational operation of the dial knob is imparted to the operator as click feeling.
Recently, to realize the reduction of the number of parts of the operation switch, there has been an attempt to use one rotary switch in common among a plurality of selection functions. In this kind of operation switch having the common use structure, a switch controller which constitutes a control unit of the input operation system brings a switch determination mode into a function selection setting mode in a switch determination initial state. At this point of time, when the dial knob is operated, in response to a switch signal acquired from the rotary switch, a vehicle-loaded equipment which the operator requires setting a function thereof is selected and designated. The switch controller, after the selection and the designation of the vehicle-loaded equipment, changes over the switch determination mode to a detail setting mode. When the dial knob is operated at this point of time, in response to a switch signal acquired from the rotary switch, the detail of the selected and designated vehicle-loaded equipment is set to a state corresponding to the switch operation.
In case of the operation switch having the common-use structure, it is desirable that the click feeling generated in the rotary switch by the detent mechanism differs for every selection function. Here, a detent changeover technique which changes over click feelings for respective selection functions using this type of operation switch having the common-use structure is disclosed in JP-A-2002-189559, for example. In the technique disclosed in JP-A-2002-189559, a plurality of discs having detent crests which differ from each other in the arrangement distance is arranged side by side in the vertical direction, and by vertically moving a detent piece by an actuator, the detent piece is selectively brought into resilient contact with detent crests of one of these discs thus changing over the click feeling acquired when a dial knob is rotatably operated.
In the technique disclosed in patent document 1, one rotary switch is used in common among the plurality of selection functions, and the click feeling generated in the dial knob can be changed over for respective selection functions. However, the technique disclosed in JP-A-2002-189559 adopts the structure which vertically moves the detent piece per se by the actuator over a plurality of discs and hence, the technique adopts the part arrangement structure in which a plurality of discs having the detent crests are arranged side by side along the direction of an operation shaft of the dial knob. Accordingly, although the operation switch described in JP-A-2002-189559 can change over the click feeling of the dial knob, the number of parts necessary for the rotary switch is increased thus giving rise to a possibility that the switch apparatus becomes large sized or a device cost is pushed up whereby there has been a demand for the reduction of the number of parts of this kind.